Quarterly Consolidated Financial Data (unaudited) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 2,082	$ 2,792	$ 2,599	$ 2,599	$ 2,354	$ 2,890	$ 2,259	$ 2,009	$ 10,072	[1]	$ 9,512	[1]	$ 8,752	[1]
Income (loss) from operations	108	682	444	358	105	568	417	(328)	1,592		762		378
Net income (loss) attributable to Calpine	$ (156)	$ 485	$ 266	$ 175	$ (16)	$ 272	$ 352	$ (598)	$ 770		$ 10		$ (339)

[1] Includes intersegment revenues of $530 million, $488 million and $324 million in the West, $946 million, $573 million and $361 million in Texas, $522 million, $234 million and $237 million in the East and $11 million, $4 million, $4 million in Retail for the years ended December 31, 2019, 2018 and 2017, respectively.